This invention relates to a system for reducing evaporation of slow moving water in an open water conveyance structure, such as an aqueduct or canal. The preferred system comprises an impervious membrane in a series of sheets that float on the surface of the water. The sheets of the floating membrane system have a lead edge that is connected to a cable that is anchored to the wall of the water structure and a trailing edge connected to a buoyant boom that extends across the water structure to spread the sheet over the flowing water.
The transport of water utilizing canals and aqueducts has been accomplished for thousands of years. Furthermore, covering the water structure has also been done to prevent contamination from debris and loss of water from evaporation. Conventionally, the canal or aqueduct has been covered by a structure that is raised above the water surface and is thereby limited by the dimension of the span. For large water conveyance structures with a wide span, the cost of any covering elevated above the water surface is typically greater than any potential savings from inhibiting water loss. In order to be cost effective, the covering for a modern, concrete water conveyance structure must be inexpensive and durable.